Mathematics
         
语言:中文    Language:English
On line solution of multivariate equations:
    First set the elements of the equation (i.e. the number of unknowns), then click the "Next" button to enter the coefficients of each element of the equation set, and click the "Next" button to obtain the solution of the equation set.
    Note that the coefficients of each element of the equation system can only be numbers, not algebraic expressions (including mathematical functions).
    Current location:Equations > Multivariate equations > Answer
detailed information:
The input equation set is:
 40x -20y + 
1
2
z = -70    (1)
-20x + 61y 
1
2
z = 91    (2)
 20x + z = 0    (3)
Question solving process:

Divide the two sides of equation (1) by 2, the equation can be obtained:
         20x -10y + 
1
4
z = -35    (4)
, then add the two sides of equation (4) to both sides of equation (2), the equations are reduced to:
 40x -20y + 
1
2
z = -70    (1)
 51y 
1
4
z = 56    (2)
 20x + z = 0    (3)

Divide the two sides of equation (1) by 2, the equation can be obtained:
         20x -10y + 
1
4
z = -35    (5)
, then subtract both sides of equation (5) from both sides of equation (3), the equations are reduced to:
 40x -20y + 
1
2
z = -70    (1)
 51y 
1
4
z = 56    (2)
 10y + 
3
4
z = 35    (3)

Multiply both sides of equation (2) by 10
Divide the two sides of equation (2) by 51, the equation can be obtained:
         10y 
5
102
z = 
560
51
    (6)
, then subtract both sides of equation (6) from both sides of equation (3), the equations are reduced to:
 40x -20y + 
1
2
z = -70    (1)
 51y 
1
4
z = 56    (2)
 
163
204
z = 
1225
51
    (3)

Multiply both sides of equation (3) by 51
Divide both sides of equation (3) by 163, get the equation:
         
163
652
z = 
1225
163
    (7)
, then add the two sides of equation (7) to both sides of equation (2), get the equation:
 40x -20y + 
1
2
z = -70    (1)
 51y = 
10353
163
    (2)
 
163
204
z = 
1225
51
    (3)

Multiply both sides of equation (3) by 102
Divide both sides of equation (3) by 163, get the equation:
         
163
326
z = 
2450
163
    (8)
, then subtract both sides of equation (8) from both sides of equation (1), get the equation:
 40x -20y = 
13860
163
    (1)
 51y = 
10353
163
    (2)
 
163
204
z = 
1225
51
    (3)

Multiply both sides of equation (2) by 20
Divide both sides of equation (2) by 51, get the equation:
         20y = 
4060
163
    (9)
, then add the two sides of equation (9) to both sides of equation (1), get the equation:
 40x = 
9800
163
    (1)
 51y = 
10353
163
    (2)
 z = 
4900
163
    (3)

The coefficient of the unknown number is reduced to 1, and the equations are reduced to:
 x = 
245
163
    (1)
 y = 
203
163
    (2)
 z = 
4900
163
    (3)


Therefore, the solution of the equation set is:
x = 
245
163
y = 
203
163
z = 
4900
163


Convert the solution of the equation set to decimals:
x = -1.503067
y = 1.245399
z = 30.061350

解方程组的详细方法请参阅:《多元一次方程组的解法》







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